Donna could feel the Doctor's thin body trembling beneath her light grasp and she was becoming more and more worried. 

"We're supposed to be best mates Spaceman, you don't have to keep anything secret from me, y'know?" She told him as she held him close to her. He was glaring at the approaching figures with a dark motive in his old eyes. "But if you want to stay, then I'm with you." 

Donna stood by the Doctor's side. She wasn't going anywhere.